1. Field of the Invention
The present invention relates to ink sets, and more particularly, relates to an ink set that is suitable for use in ink jet recording in which an ink is ejected from an orifice in response to a recording signal in order to perform recording on a recording medium, as well as to an ink jet recording apparatus, an ink jet recording method, a recording unit, and an ink cartridge.
2. Description of the Related Art
Conventionally, aqueous inks in which dyes having various color tones are dissolved in water-soluble media are used for color recording using an ink jet recording method. It is desirable that the inks exhibit the following ink jet recording characteristics (1) to (10) at as high a degree as possible.                (1) Produces images with adequate density;        (2) Satisfactorily dries on a recording medium;        (3) Smearing of the recorded image does not occur;        (4) Running of the recorded image does not occur when in contact with water, alcohols, etc.;        (5) A recorded image with superior light-fastness is produced;        (6) Does not cause clogging at nozzles;        (7) Blurring of recorded images does not occur during continuous printing or when recording is started after a long interval;        (8) Stable when stored;        (9) Problems do not occur even if inks are brought into contact with components of the recording apparatus; and        (10) Has superior heat resistance and does not affect thermal energy generation elements.        
Furthermore, as demand for color ink jet recording increases, images of higher resolution and higher quality are being required. For these purposes, color images in the broad color reproduction range are achieved by selecting coloring materials having superior color developing ability, and the dot size of images is decreased by producing small ink droplets, thereby achieving images with high resolution. Furthermore, by using two or more types of inks which have different coloring material contents but the same color tone, the inks can be selected depending on the density of the image, i.e., light color portions and deep color portions, and by controlling various ink-applying processes, it is possible to produce smoother images. Using the techniques described above, ink jet recording methods have recently been producing ink jet images of high quality, which are comparable to silver halide photographs.
However, even if ink jet images of a quality comparable to silver halide photographs are produced using the techniques described above, the color balance may become unstable depending on the environment in which the images are stored and the visual appearance of the image may degrade, resulting in a loss in durability of the images. Therefore, there is an increased demand for an ink jet image which has, in addition to high resolution, even more superior durability, for example, and which does not fade substantially even if stored for a long period of time.